my least favorite is point lookout, the reason is there are no towns, no settlements, nobody to interact with really except a person here or there. its mostly all water if you look at the map, no big complexes or buildings to go in, there isn't a lot of exploration to point lookout, unless you think swampland and water is good for exploring. they could of put a few actual towns there with some people. the pitt is way better for exploring and more immersive, too bad the pitt was so small, but i still think its the best dlc for game immersion and exploration. broken steel is good and OA is good mainly because i like gauss rifle. but point lookout svcks and i hope to never see dlc like that again, the quests were good in point lookout actually but the georgraphy of the land was lousy and there just too much water, way too much, water everywhere.
I mostly agree with rockies comments about point lookout, the fun or novelty though was having somewhere new to go outside of the wasteland. I had to use the wiki for point lookout because I thought I had missed a load of content but I hadn't. Anchorage puts me to sleep. The first playthrough was fine, enjoyable for brief periods but I came to resent having to do the DLC to get the items I wanted at the end, thankfully door unlock commands came to my rescue.
I enjoyed the pitt most of all for the same reasons explained in other peoples posts, followed by mothetship zeta (characters, environment, storyline, equipment, even more equipment!) , supurb replayability for those 2 DLC for me but not everyones cup of tea I know.
However broken steel adds so much to the vanila game in terms of levels, perks, new quests, few new enemies, no forced ending etc. Although the pitt is my favourite I always recommend people get Broken Steel first.
Most disapointing is Mothership Zeta becasue of the bugs, save often so you can reload if needed...